Synchronization, Doppler and channel estimation for OFDM underwater acoustic communications

Trubuil, J.; Gall, Thierry Le; Chonavel, Thierry

doi:10.1109/oceans-taipei.2014.6964330

Cited by 9 publications

(5 citation statements)

References 4 publications

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“…The results show that the synchronization mechanism has better accuracy. Trubuil et al [ 51 ] propose an estimation technique with a dual-training sequence of the Doppler shift. Experiments show that the method is effective in acoustic communication.…”

Section: Related Workmentioning

confidence: 99%

PCDE-Sync: A Time Synchronization Mechanism Based on Partial Clustering and the Doppler Effect for Underwater Acoustic Networks

Wang

Feng

et al. 2022

Computational Intelligence and Neuroscience

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Time synchronization is the basis of coordination and cooperation in underwater acoustic networks. However, because of the propagation delay, node mobility, and Doppler shift, it is impossible to balance the accuracy and energy consumption simply in water. As a promising technology, partial clustering has high convergence and makes breakthroughs in time synchronization. This paper proposes PCDE-Sync, a novel synchronization mechanism with partial clustering and the Doppler effect. Firstly, a clustering method built on the artificial fish swarm algorithm is presented. It models the cluster construction according to fish's preying, swarming, and following behaviors. Secondly, we design a synchronization mechanism to conduct clock correction and compensation by the Doppler effect. Finally, we compare the performance of PCDE-Sync with the most advanced protocols, namely MU-Sync, MM-Sync, and DE-Sync, in terms of the cumulative error after synchronization, the mean square error under different clock skew and that under distinctive node mobility, and energy consumption. The experimental results show that PCDE-Sync makes a trade-off between accuracy and complexity, which does well in solving synchronization issues.

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Section: Related Workmentioning

confidence: 99%

PCDE-Sync: A Time Synchronization Mechanism Based on Partial Clustering and the Doppler Effect for Underwater Acoustic Networks

Wang

Feng

et al. 2022

Computational Intelligence and Neuroscience

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“…[70,73,77] have analyzed various modulation techniques. There has also been work on underwater channel estimation for OFDM [56,82], the use of pilot symbols to track channel estimates within a packet [44,76], Doppler estimation [39,49,81] and bit rate adaptation [25,59,67,71,75,78] for underwater sensor networks. Various hardware MAC protocols [24] have also been explored in prior work.…”

Section: Related Workmentioning

confidence: 99%

Underwater messaging using mobile devices

Chen

Chan

Gollakota

2022

Proceedings of the ACM SIGCOMM 2022 Conference

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Since its inception, underwater digital acoustic communication has required custom hardware that neither has the economies of scale nor is pervasive. We present the first acoustic system that brings underwater messaging capabilities to existing mobile devices like smartphones and smart watches. Our software-only solution leverages audio sensors, i.e., microphones and speakers, ubiquitous in today's devices to enable acoustic underwater communication between mobile devices. To achieve this, we design a communication system that in real-time adapts to differences in frequency responses across mobile devices, changes in multipath and noise levels at different locations and dynamic channel changes due to mobility. We evaluate our system in six different real-world underwater environments with depths of 2-15 m in the presence of boats, ships and people fishing and kayaking. Our results show that our system can in real-time adapt its frequency band and achieve bit rates of 100 bps to 1.8 kbps and a range of 30 m. By using a lower bit rate of 10-20 bps, we can further increase the range to 100 m. As smartphones and watches are increasingly being used in underwater scenarios, our software-based approach has the potential to make underwater messaging capabilities widely available to anyone with a mobile device.Project page with open-source code and data can be found here: https://underwatermessaging.cs.washington.edu/ CCS CONCEPTS• Networks → Mobile networks; • Applied computing → Environmental sciences; • Human-centered computing → Ubiquitous and mobile devices;

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“…To preserve the performance of the UWA‐OFDM system, the effect of the CFO must be compensated. There are different estimation and compensation algorithms for CFO in UWA‐OFDM systems …”

Section: Introductionmentioning

confidence: 99%

“…There are different estimation and compensation algorithms for CFO in UWA-OFDM systems. [18][19][20][21][22] The problems associated with the UWA-OFDM must be taken into account to mitigate the impairments of the OFDM over the underwater channels. In this paper, we are concerned with the CFO compensation.…”

mentioning

confidence: 99%

Joint low‐complexity equalization and carrier frequency offset compensation for underwater acoustic OFDM communication systems with banded‐matrix approximation at different channel conditions

Ramadan¹,

Dessouky

El-Kordy

et al. 2018

Int J Communication

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Summary Underwater acoustic wireless communication is considered as one of the most challenging communication technologies due to low propagation speed, water salinity, water depth, PH degree, and water temperature. Equalization is one of the means to improve the system performance. Matched filter (MF), zero forcing (ZF), and minimum mean square error (MMSE) equalizers can be used for channel equalization. Unfortunately, the performance of the matched filter is destroyed in the Multiple‐Input Multiple‐Output (MIMO) configurations. In addition, the ZF equalizer suffers from noise enhancement and high complexity because of the direct matrix inversion. On the other hand, the MMSE equalizer requires estimating the operating signal‐to‐noise ratio (SNR) to work properly. In this paper, we present a joint low‐complexity regularized ZF equalizer and carrier frequency offset (CFO) compensation scheme to deal with these problems. The proposed equalization algorithm mitigates the noise enhancement problem using a constant regularization parameter, and it can be implemented with low complexity using the banded‐matrix approximation. Also, we test the performance of the proposed system at different channel conditions. Simulation results show that the proposed equalizer has the ability to enhance the system performance with lower complexity than those of the other equalization algorithms at different channel conditions.

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Synchronization, Doppler and channel estimation for OFDM underwater acoustic communications

Cited by 9 publications

References 4 publications

PCDE-Sync: A Time Synchronization Mechanism Based on Partial Clustering and the Doppler Effect for Underwater Acoustic Networks

PCDE-Sync: A Time Synchronization Mechanism Based on Partial Clustering and the Doppler Effect for Underwater Acoustic Networks

Underwater messaging using mobile devices

Joint low‐complexity equalization and carrier frequency offset compensation for underwater acoustic OFDM communication systems with banded‐matrix approximation at different channel conditions

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